Battle.net announces an "important security update," revealing Blizzard has discovered "unauthorized and illegal access into our internal network." As a result, they recommend that North American users change their passwords, though they say they believe that the information retrieved "alone is NOT enough for anyone to gain access to Battle.net accounts." They also have written up an Important Security Update FAQ with all the details on this, including the surprising news that "information was taken that could potentially compromise the integrity of North American Mobile Authenticators," which will lead to a software updates.